Unsaturated ester as perfuming ingredient

ABSTRACT

The present invention relates to a compound of formula  
                 
 
     wherein R represents a methyl or an ethyl group, in the form of any one of its isomers or of a mixture thereof. The invention relates also to the use of such a compound as a perfuming ingredient capable of imparting a odorant note of the rose type. Moreover, the invention concern also the perfumed article or perfuming composition containing a compound according to the invention.

BRIEF SUMMARY OF THE INVENTION

[0001] The present invention relates to the perfume industry. Itconcerns more particularly a compound of formula

[0002] wherein R represents a methyl or an ethyl group, in the form ofany one of its isomers or of a mixture thereof. The invention alsorelates to the use of such a compound as a perfuming ingredient and tothe perfumed article or perfuming composition containing a compoundaccording to the invention.

PRIOR ART

[0003] Although several similar structures are known in the literature,to the best of our knowledge, the compounds of the present inventionhave novel chemical structures.

[0004] A 1/1 mixture of ethyl esters of formula (I) having thecarbon-carbon double bond in position 3 or 4 of the ring is described inU.S. Pat. No. 3,887,625. However in said document there are no usefulindications that could allow a person skilled in the art to obtain anester according to the invention (e.g. having the carbon-carbon doublebond only in position 3). Furthermore, in the prior art there is nomention or suggestion of any organoleptic properties of the compounds offormula (I), or of any potential use of said compounds as perfumingingredients.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0005] Surprisingly, we have now established that the compounds offormula

[0006] wherein R represents a methyl or an ethyl group, in the form ofany one of its isomers, namely the (1R,2R), (1R,2S), (1S,2R) or the(1S,2S) isomers, or of a mixture thereof, possess a surprising and veryuseful damascone-like fragrance, which render them very convenient forthe preparation of perfumes, perfuming compositions and perfumedproducts.

[0007] Amongst the compounds of formula (I), the methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate is much appreciatedfor its odor which presents a remarkable damascone, rosy note associatedwith citronellol like and slightly saffrony notes. The damascone note isparticularly nice and has a very natural, very rosy, more precisely redrose odor. Moreover, said odor is devoid of the fermented-apple aspectpresent for example in the alpha damascone fragrance. From an olfactorypoint of view, the odor character of methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate is intermediatebetween that of delta and alpha damascone. Nevertheless, and despitethis odor similarity, the use of the invention compounds has been provedto be more versatile than that of the damascones.

[0008] Furthermore, perfumers have also noticed some differences betweenthe two enantiomers of the trans methyl ester, namely the (1R,2S) andthe (1S,2R) methyl 2,6,6-trimethyl-3-cyclohexene-1-carboxylate. Indeed,although the odor of both enantiomers is clearly damascone-like and inthe same trend described hereinabove, the fragrance of the (1R,2S)enantiomer is stronger that the one of the (1 S,2R) enantiomer which, inthe other hand, is more aromatic.

[0009] In addition to the typical rose, damascone-like note of thecompounds of formula (I), the methylcis-2,6,6-trimethyl-3-cyclohexene-1-carboxylate possesses also terpenicand carrot tops notes.

[0010] The ethyl trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylatedevelops a damascone-like odor similar to that of the correspondingtrans methyl ester. The similarity of the odor of the ethyl and methylester is quite surprising in view of the prior art, wherein the methyland ethyl esters of known analogues have in general significantlydifferent odor properties.

[0011] The preferred compounds of the invention are the methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate and the (1R,2S) methyl2,6,6-trimethyl-3-cyclohexene-1-carboxylate.

[0012] The character and the quality of the odor properties of theinvention compounds are all the more surprising and unexpected in viewof the odor of their prior art analogues.

[0013] Indeed, the trans methyl ester of formula (I) possesses an odorcloser to that of damascones than its gamma or alpha isomers, namelymethyl 2,2-dimethyl-6-methylene-1-cyclohexanecarboxylate (described inU.S. Pat. No. 5,015,625, to Firmenich S A) and methyl2,6,6-trimethyl-2-cyclohexene-1-carboxylate (described in EP 56109)respectively. This effect is mainly due to the fact that, when comparedwith the mentioned isomers, the trans methyl ester presents a more puredamascone-rosy connotation, which is almost devoid of the typicalherbaceous-thujonic and red-fruity, green apple notes of said gamma andalpha isomer.

[0014] Similarly, when the trans ethyl ester of formula (I) is comparedwith the ethyl gamma isomer, also described in U.S. Pat. No. 5,015,625,then the invention compound distinguishes itself from the prior knowncompound in that it presents a rosy odor devoid of the metallic,herbaceous-thujonic notes characteristic of the prior art analogue.

[0015] The compounds of the invention are suitable for use in fineperfumery, in perfumes, colognes or after-shave lotions, as well as inother current uses in perfumery such as to perfume soaps, preparationsfor the shower or the bath, such as bath salts, mousses, oils, gels orother preparations, products such as body oils, body-care products, bodydeodorants and antiperspirants, hair care products such as shampoos,ambient air deodorants, or cosmetic preparations.

[0016] The compounds of formula (I) can also be used in applicationssuch as liquid or solid detergents for textile treatment, fabricsofteners, or also in detergent compositions or cleaning products forcleaning dishes or varied surfaces, for industrial or household use.

[0017] In these applications, the compounds according to the inventioncan be used alone, as well as mixed with other perfuming ingredients,solvents, adjuvants or additives commonly used in perfumery. The natureand variety of these co-ingredients do not require a more detaileddescription here, which would not be exhaustive anyway. In fact, aperson skilled in the art, having a general knowledge, is able to choosethem according to the nature of the product that has to be perfumed andthe olfactory effect sought. These perfuming co-ingredients belong tovaried chemical groups such as alcohols, aldehydes, ketones, esters,ethers, acetates, nitrites, terpenic hydrocarbons, heterocyclicnitrogen- or sulfur-containing compounds, as well as natural orsynthetic essential oils. Many of these ingredients are listed inreference texts such as S. Arctander, Perfume and Flavor Chemicals,1969, Montclair, N.J., USA, or more recent versions thereof, or in othersimilar books, or yet in the specialized patent literature commonlyavailable in the art.

[0018] The proportions in which the compounds according to the inventioncan be incorporated in the different products mentioned above vary in abroad range of values. Indeed, we have found that the compounds of theinvention are environmentally friendly and not sensitizing, and thiseven at relatively high concentrations. The range of concentrationsdepends on the nature of the product to be perfumed and on the olfactoryeffect sought, as well as on the nature of the co-ingredients in a givencomposition when the compounds of the invention are used in admixturewith perfuming co-ingredients, solvents or additives commonly used inthe art.

[0019] For instance, concentrations from 0.1% to 1.5%, and preferablyfrom 0.3% to 0.8%, by weight of these compounds, with respect to theperfuming composition in which they are incorporated, can be typicallyused. Lower concentrations than these can be used when these compoundsare directly applied for perfuming some of the consumer productsmentioned above.

[0020] The synthesis of the compounds of formula (I), which is anotherobject of the present invention, is characterized by a rearrangementreaction which provides directly a final product having a carbon-carbondouble bond selectively in the position 3. Said rearrangement reactionis characterized by the reaction of a α-β unsaturated tosyl hydrazone offormula

[0021] wherein R represents a methyl or ethyl group,

[0022] in the presence of a borane derivative, such as NaBH₄ or catecholborane ((C₆H₄O₂)BH), and a carboxylate derivative selected in the groupconsisting of the C₁-C₈ carboxylic acids and their alkaline salts.Preferably the borane derivative is catechol borane and the carboxylatederivative is a sodium or potassium salt of a C₂-C₄ carboxylic acid.

[0023] This synthesis provides the compounds of formula (I) as a mixtureof four possible isomers. The two diastereomers, namely the trans andcis isomers, may be subsequently separated by using conventionalmethods, such as recrystallization or chromatography. Finally, theenantiomers of each diastereomer may be separated by recrystallisazionof the ephedrate salt of the free acid derivative, as will be describedin the examples.

[0024] The invention will now be described in further detail by way ofthe following examples, wherein the temperatures are indicated indegrees centigrade (°C.); the NMR spectral data were recorded with a 360MHz machine in CDCl₃; the chemical displacement δ are indicated in ppmwith respect to the TMS as standard and all the abbreviations have theusual meaning in the art.

DESCRIPTION OF THE INVENTION Example 1

[0025] Synthesis of Methyl (Trans/Cis)2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0026] a) Methyl2,2,6-trimethyl-4-[(4-methylphenylsulfonyl)hydrazono]-2-cyclohexene-1-carboxylate

[0027] A suspension of p-toluenesulfonylhydrazide (96.80 g, 0.520 mol)in a solution of methyl2,2,6-trimethyl-4-oxo-2-cyclohexene-1-carboxylate (92.71 g, 0.473 mol)and AcOH (0.463 g, 4.7 mmol) in MeOH (500 ml) was heated at reflux in a1.5 l three necked flask, fitted with a mechanical stirrer.

[0028] Upon heating the reaction mixture became clear and, once atreflux temperature, the formed hydrazone gradually precipitated. Heatingwas prolonged for 6 h, then the reaction mixture was cooled at 0° andthe precipitated solid was collected by filtration affording 153.80 g ofpure hydrazone. Crystallization of the mother liquors from MeOH (55 ml)gave a second portion of pure hydrazone (2.90 g) (yield=91%).

[0029]¹H-NMR: 0.92(s, 3H); 1.02(s, 3H); 1.80(s, 3H); 2.13(d, J=16.0,1H); 2.39(d, J=16.0, 1H); 2.77(s, 3H); 3.66(s, 3H); 6.08(s, 1H); 7.29(d,J=8.0 Hz, 2H); 7.84(d, J=8.0, 2H).

[0030]¹³C-NMR: 172.3(s); 154.1(s); 144.0(s); 140.3(s); 135.4(s);129.6(d); 128.0(d); 124.5(d); 57.5(d); 51.92(q); 33.7(t); 33.4(s);28.4(q); 27.3(q); 23.1(q); 21.6(q).

[0031] b) Methyl 2,6,6-trimethyl-3-cyclohexene-1-carboxylate andSeparation of Trans and Cis Diastereomers

[0032] In a three necked 2 l flask fitted with a mechanical stirrer,catechol borane (15.25 g, 0.126 mol) was added in 15 minutes, at 0° C.,to a suspension of the hydrazone obtained in a) (38.45 g, 0.105 mol) inCHCl₃ (500 ml). After 2 hours, to the yellow reaction mixture, still at0° C., AcONa.3H₂O (28.7 g, 0.211 mol) was added at once. After 30minutes, the reaction mixture was heated at reflux for 1 hour, thencooled at 25° and the white solid filtered off on Celite. The cake waswashed with three portions of CHCl₃, and the combined filtrates wereevaporated under reduced pressure. The crude material was dissolved inpentane, the organic layer washed (5% aqueous NaOH, H₂O and brine),dried (Na₂SO₄), filtered and concentrated. Bulb-to-bulb distillation(75-120°/3 mbar) of the crude product afforded 8.55 g of methyl2,6,6-trimethyl-3-cyclohexene-1-carboxylate as a trans/cis=86:14 mixture(yield=43%).

[0033] Crystallization of the thus obtained product, at −78° frompentane (9.5 ml), afforded 6.39 g of methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate (trans/cis=96:4), andconcentration of the crystallization mother liquors gave 2.13 g ofmethyl 2,6,6-trimethyl-3-cyclohexene-1-carboxylate in the form of atrans/cis=54:46 mixture.

[0034] Two flash chromatograph separations (SiO₂,cyclohexane/AcOEt=97:3) of the compounds issued from the mother liquorsgave 0.9 g of the cis diastereomer as a trans/cis=10:90 mixture.

[0035] Methyl Trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0036]¹H-NMR: 0.93(d, J=6.5, 3H); 0.95(s, 3H); 0.99(s, 3H); 1.74(d,J=18.0, 1H); 1.95(d, J=18.0, 1H); 2.04(d, J=11.5, 1H); 2.52(m, 1H);3.69(s, 3H); 5.47(d, J=10.0, 1H); 5.52-5.59(m, 1H).

[0037]¹³C-NMR: 175.3(s); 131.1(d); 124.4(d); 57.6(d); 51.0(q); 41.1(t);32.3(s); 31.6(d); 29.6(q); 20.9(q); 20.0(q).

[0038] MS: 182(M⁺, 20); 151(10); 127(14); 126(16); 125(41); 123(66);122(93); 114(13); 111(23); 108(17); 107(100); 96(13); 95(23); 93(22);91(37); 83(19); 82(30); 81(43); 79(28); 77(27); 69(21); 68(28); 67(43);65(16); 59(16); 55(21); 53(24); 51(10); 43(16); 39(41); 29(21); 27(22).

[0039] Methyl Cis-2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0040]¹H-NMR: 0.95(s, 3H); 0.97(s, 3H); 0.98(d, J=7.5, 3H); 1.66(d,J=18.0, 1H); 2.28(d, J=18.0, 1H); 2.37(d, J=6.0, 1H); 2.52(m, 1H);3.61(s, 3H); 5.40(d, J=10.0, 1H); 5.65-5.73(m, 1H).

[0041]¹³C-NMR: 173.9(s); 128.2(d); 125.8(d); 54.6(d); 50.6(q); 35.6(t);31.3(s); 29.6(d); 29.5(q); 29.0(q); 17.7(q).

[0042] MS: 182(M⁺, 24); 167(10); 151(13); 127(16); 126(19); 125(43);122(100); 114(14); 111(20); 108(15); 107(89); 95(18); 93(16); 91(25);83(15); 82(28); 81(32); 79(16); 77(15); 69(18); 68(24); 67(30); 55(11);53(10); 41(19); 39(11).

Example 2

[0043] Synthesis of the Enantiomers of the Methyl Trans2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0044] a) (±)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid

[0045] A suspension of KOH (4.34 g, 77.5 mmol) in a solution of methyltrans 2,6,6-trimethyl-3-cyclohexene-1-carboxylate (13.48 g, 74.1 mmol)and thiophenol (8.51 g, 77.5 mmol) in DMF (60 ml) was heated at 100° ina three necked 250 ml flask fitted with a stirrer. After 16 hours, thecooled mixture was poured onto cold aqueous HCl (0.5 M, 200 ml) andextracted with Et₂O. The crude compound was pre-purified by standardacid-base extraction. The organic phase was dried (Na₂SO₄), filtered,concentrated, and then heated for 4 h at 100°/4 mbar to remove theexcess of thiophenol. Bulb-to-bulb distillation (100-130°/0.1 mbar)afforded 10.57 g of the racemic acid as a trans/cis=96:4 mixture(yield=85%).

[0046]¹H-NMR: 1.02(s, 3H); 1.03(d, J=7.6 Hz, 3H); 1.05(s, 3H); 1.77(d,J=18.0, 1H); 1.97(d, J=18.0, 1H); 2.04(d, J=10.0, 1s); 2.50(m, 1s);5.47(d, J=10.0, 1H); 5.53-5.60(m, 1H); 11.35-11.85(s, 1H).

[0047]¹³C-NMR: 181.4(s); 130.9(d); 124.4(d); 57.6(d); 41.1(t); 32.2(s);31.1(d); 29.5(q); 20.9(q); 20.0(q).

[0048] MS: 168(M⁺, 91); 153(33); 125(34); 124(58); 113(58); 112(46);111(100); 109(36); 108(20); 107(83); 101(13); 100(27); 97(26); 95(25);91(36); 83(13); 82(65); 81(44); 79(24); 77(24); 69(58); 68(52); 67(60);65(13); 56(18); 55(15); 53(13); 43(13); 41(24); 39(16).

[0049] b) (−)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid

[0050] In a 100 ml flask equipped with a mechanical stirrer, a solutionof (−)-ephedrine (Fluka, 5.64 g, 34.2 mmol) in an hexane-acetone mixture(75:25, 27 ml) was added in 5 minutes to a solution of(±)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid (7.65 g, 45.5mmol) in hexane (20 ml). After stirring for 45 minutes, the suspensionvas cooled at 0° and filtered to afford 5.61 g of ephedrate salt (65%ee) and a mother liquor. Two crystallizations of the ephedrate salt froma toluene-hexane mixture (60:40) afforded 4.08 g of pure ephedrate saltand the corresponding mother liquors. The pure ephedrate salt thusobtained was dissolved in methanol (45 ml) and treated at 25° with 5%aqueous HCl (10.5 ml). After half an hour, the reaction mixture wasconcentrated and the residue dissolved in AcOEt (100 ml). The organicphase was washed (H₂O and brine), dried (Na₂SO₄), filtered andconcentrated. A bulb-to-bulb distillation (100-130°/0.1 mbar) afforded2.01 g of pure (−)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid(98% ee determined by chiral GC on CP-Chirasil-DEX CB).

[0051] [α]_(D) ²⁰ (CHCl₃, c=14 g/l)=−97.3

[0052] NMR: as previously described for the racemic compound.

[0053] c) (+)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid

[0054] The combined mother liquors obtained in b) (9.14 g of salt) wereregenerated using the same procedure as described in b) to provide thefree acid. A bulb-to-bulb distillation (100-130° C./0.1 mbar) afforded5.20 g of (+)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid(ee=41%). The free acid was thus treated with (+)-ephedrine hemihydrate(Sigma, 5.39 g, 31.0 mmol) as described herein above for the otherenantiomer to obtain 8.91 g of ephedrate salt (49% ee). Twocrystallizations, as descibed in b), of the salt afforded 5.55 g of puresalt (97% ee). The pure ephedrate salt thus obtained was dissolved inmethanol (58 ml) and treated with 5% aqueous HCl (14.5 ml). After halfan hour, the reaction mixture was concentrated and the residue dissolvedin AcOEt (100 ml). The organic phase was washed (H₂O and brine), dried(Na₂SO₄), filtered and concentrated. A bulb-to-bulb distillation(100-130°/0.1 mbar) afforded 2.01 g of pure(+)-trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid (98% eedetermined by chiral GC on CP-Chirasil-DEX CB).

[0055] [α]_(D) ²⁰ (CHCl₃, c=12 g/l)=+100.9

[0056] NMR: as previously described for the racemic compound.

[0057] d) (+) or (−)-methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0058] In a three necked 100 ml flask, a solution of the desiredenantiomer of free acid obtained in b) or c) (1.85 g, 1.0 mmol),methyliodide (1.87 g, 15.8 mmol), and K₂CO₃ (1.82 g, 15.8 mmol) in DMF(40 ml) was stirred at 40° C. for 2 hours. The cooled reaction mixturewas poured onto cold 5% aqueous HCl and extracted twice with pentane.The organic phases were washed (three times with H₂O and brine), dried(Na₂SO₄), filtered and concentrated. A bulb-to-bulb distillation (100°/4mbar) afforded 1.8 g of desired methyl ester (yield=90%).

[0059] (−)-Methyl (1S,2R)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0060] [α]_(D) ²⁰ (CHCl₃, c=28 g/l)=−83.3

[0061] NMR: as previously described for the racemic compound.

[0062] (+)-Methyl (1R,2S)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0063] [α]_(D) ²⁰ (CHCl₃, c=29 g/l)=−83.1

[0064] NMR: as previously described for the racemic compound.

Example 3

[0065] Synthesis of Ethyl Trans2,6,6-trimethyl-3-cyclohexene-1-carboxylate

[0066] In a three necked 100 ml flask a suspension oftrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylic acid obtained inexample 2 a) (0.800 g, 4.8 mmol), ethylbromide (0.616 g, 5.7 mmol) andK₂CO₃ (0.787 g, 5.7 mmol) in DMF (20 ml) was stirred at 40° C. for 2 h.The cooled reaction mixture was next poured onto cold 5% aqueous HCl andextracted twice with pentane. The organic phases were washed (threetimes with H₂O and brine), dried (Na₂SO₄), filtered and concentrated. Abulb-to-bulb distillation (100°/4 mbar) afforded 0.870 g of ethyl trans2,6,6-trimethyl-3-cyclohexene-1-carboxylate in the form of atrans/cis=96:4 mixture (yield=84%).

[0067]¹H-NMR: 0.94(d, J=6.5, 3H); 0.96(s, 3H); 0.99(s, 3H); 1.28(t,J=7.6, 3H); 1.73(d, J=18.0, 1H); 1.96(d, J=18.0, 1H); 2.02(d, J=10.4,1H); 2.52(m, 1H); 4.16(q, J=7.6, 2H); 5.46(d, J=10.0, 1H); 5.52-5.59(m,1H).

[0068]¹³C-NMR: 174.7(s); 131.2(d); 124.3(d); 59.8(t); 57.7(d); 41.2(t);32.3(s); 31.3(d); 29.4(q); 20.9(q); 19.9(q); 14.4(q).

[0069] MS: 196(23); 151(17); 139(18); 123(84); 122(100); 121(21);112(25); 111(15); 108(14); 107(86); 95(15); 93(22); 91(30); 83(10);82(22); 81(45); 79(23); 77(22); 69(15); 68(18); 67(32); 65(13); 55(18);53(17); 42(18); 41(38); 39(26); 29(38); 27(24).

Example 4

[0070] Preparation of a Perfuming Composition

[0071] A “fruity” type base composition was prepared by admixing thefollowing ingredients: Ingredient Parts by weight 10%* Amyl acetate  1010%* 3-Methyl-2-butenyl acetate  30 10%* Aldehyde C6  30 Hexylcinnamicaldehyde 100 Ethyl anthranilate  5 2-Methyl-4-phenyl-2-butanol  30Methyl cinnamate  10 10%* Cis-3-hexenol  30 Dihydro Eugenol  5 10%*β-Dorinone ® ¹⁾  20 Diethyl 1,4-cyclohexanedicarboxylate ²⁾  60Habanolide ® ³⁾  60 Hedione ® ⁴⁾ 120 Alpha ionone  50 10%* Cis-3-hexenolisobutyrate  20 Phenylethyl isobutyrate  30 10%* Cognac oil  20 Methylisoeugenol  20 Muscenone Delta ⁵⁾  10 Florol ® ⁶⁾  50 Phenethylol 150Cis-3-hexenol salicylate  10 10%* Vanilline  25 Bergamot essential oil 40 Parmantheme ⁷⁾  5 940

[0072] The addition of 100 parts by weight of methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate to the above-describedcomposition imparted to the latter a pronounced rose connotation. Theolfactory effect provided by the addition of the invention compound issimilar to that provided by 6-damascone. Moreover, this olfactory effectwas less fruity-blackberry-blueberry than the one obtained by adding thesame amount of the prior known gamma isomer (methyl2,2-dimethyl-6-methylene-1-cyclohexanecarboxylate), and was also moreelegant and more damascone-like than the effect that can be obtainedwith the other known structural analogues, e.g. the alpha isomer of theinvention compound.

Example 5

[0073] Preparation of a Perfuming Composition

[0074] An “aromatic” type composition was prepared by admixing thefollowing ingredients: Ingredient Parts by weight Allyl amyl glycolate 30 Bergamot essential oil 100 Cetalox ® ¹⁾  10 Coumarine  10Dihydromyrcenol 300 Estragol  10 Exaltenone ²⁾  30 10%* Galbanumessential oil  10 Hedione ® HC ³⁾  70 Habanolide ® ⁴⁾  80 10%*Isobutylquinoleine  40 Lavandin essential oil  40 Crystal moss  40Polysantol ® ⁵⁾  20 Patchouli essential oil  80 10%* Triplal ⁶⁾  40Galbex ® ⁷⁾ 183  60 970

[0075] The addition of 300 parts by weight of methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate to the above-describedcomposition imparted to the latter a fruity, green, damascone-like, rosyodor. This effect was reminiscent of the fragrance generally imparted bydelta damascone, but it was at the same time more fruity and lessfloral.

Example 6

[0076] Preparation of a Perfuming Composition

[0077] A “fruity-citrus” type base composition was prepared by admixingthe following ingredients: Ingredient Parts by weight Benzyl acetate  20Geranyl acetate  20 Linalyl acetate 150 10%* 2-Methyldecanal  20Dihydromyrcenol 140 Habanolide ® ¹⁾  20 Lemongrass  15 Limette  20Liminal ® ²⁾  5 Linalool 100 Hedione ® ³⁾  60 Muscenone 4)  20 10%**(Z)-3-Decenal ⁵⁾  30 10%* Oxane ⁶⁾  10 10%* Rose oxide  20 Orangeessential oil 300 950

[0078] The addition of 50 parts by weight of methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate to the above-describedbase composition imparted to the latter a rosy and red apple effect.When the gamma or the alpha isomers were used instead of the compound ofthe invention, the effect was aromatic-rosemary and fruity-blueberry, ormore cellar, herbaceous and earthy, respectively.

1. A compound of formula

wherein R represents a methyl or an ethyl group, in the form of any oneof its isomers or of a mixture thereof.
 2. As a compound according toclaim 1, methyl trans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate,methyl cis-2,6,6-trimethyl-3-cyclohexene-1-carboxylate, ethyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate, methyl(1R,2S)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate or methyl(1S,2R)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate.
 3. As a compoundaccording to claim 1, methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate or methyl(1R,2S)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate.
 4. A method toimprove, enhance or modify the odor of a perfume or a perfumingcomposition, which method comprises adding to said perfume orcomposition a compound as defined in claim
 1. 5. A perfuming compositionor a perfumed product comprising as perfuming ingredient a compound offormula

wherein R represents a methyl or an ethyl group, in the form of any oneof its isomers or of a mixture thereof, together with a currentperfuming co-ingredient, solvent or adjuvant.
 6. A perfuming compositionor a perfumed product according to claim 5, characterized in that theperfuming ingredient is methyltrans-2,6,6-trimethyl-3-cyclohexene-1-carboxylate or methyl(1R,2S)-2,6,6-trimethyl-3-cyclohexene-1-carboxylate.
 7. A perfumingcomposition or a perfumed product according to claim 5, in the form of aperfume or a cologne, a perfumed soap, a shower or bath gel, a shampoo,a body deodorant or antiperspirant, an ambient air deodorant, a liquidor solid detergent for textile treatment, a detergent composition or acleaning product for dishes or varied surfaces, a fabric softener or acosmetic preparation.